ChDrive Statement

---

Named Arguments

No

Syntax

ChDrive driveletter

driveletter

Use: Required

Data Type: String

The letter of the drive (A-Z) to set as the new default drive.

Description

Changes the current working (default) disk drive.

Rules at a Glance

• If a zero-length string is supplied, the drive isn't changed.

• If driveletter consists of more than one character, only the first character determines the drive.

Example

The following example demonstrates a utility function that uses ChDrive to determine if a given drive is available. By centralizing the test, the function reduces the amount of coding required each time you need to use ChDrive:

Private Function IsAvailableDrive(sDrive As String) _
                 As Boolean
    
   'if an error occurs goto to the next line of code
   On Error Resume Next
    
   Dim sCurDrv As String
    
   'get the letter of the current drive
   sCurDrv = Left$(CurDir$, 1)
   'attempt to change the drive
   ChDrive sDrive
   'did an error occur?
   If Err.Number = 0 Then
      'no - this drive is OK to use
      IsAvailableDrive = True
   Else
      'yes - don't use this drive
      IsAvailableDrive = False
   End If
   'set the drive back to what it was
   ChDrive sCurDrv
        
End Function

The following snippet shows how this function could be implemented within your application:

If IsAvailableDrive(sDrv) Then
   ChDrive sDrv
Else
   MsgBox "Cannot use Drive " & sDrv & ":"
End If

Programming Tips and Gotchas

• On the Macintosh, ChDrive changes the current folder to the root folder of the specified drive. On Windows systems, the default directory is unaffected by the ChDrive statement.

• As ChDrive processes only the first letter of the driveletter string, it isn't possible to supply a piped name network drive name (e.g., //NTServer/ ); instead, the machine your program is running on must have a drive letter mapped to the network resource using Explorer or other network commands. If driveLetter is specified as a UNC path, the function raises error number 5, "Invalid procedure call or argument."

• If driveLetter is invalid, the function returns error number 68, "Device unavailable."

• If you are using VB6, you will find that the new File System Objects offer much more flexibility than the intrinsic drive and directory statements, especially when it comes to dealing with network drives.

See Also

ChDir Statement, File System Objects